Cameron Laird of the UnixReview just reviewed the latest iteration of Komodo IDE. Here are a few highlights from the review:

"[Komodo is] unusual in several regards: while it's proprietary (a standard license costs US $295), a single license serves whether you're developing under Linux (both libccp5 and libcpp6), Mac OS X (both PowerPC and Intel), or Windows. Also, it's an IDE not for a single language, but a whole family of dynamic languages: Perl, PHP, Python, Ruby, and Tcl. I need to be more precise about that last: Komodo supports those five languages well."

"I know of no other editor that handles multi-language source files, as are common in Web development, so smoothly but intelligently as Komodo."

"Komodo remains 'lightweight', though, at least in comparison to mainstream IDEs you're likely to encounter. It's entirely feasible to download and install a trial copy in a few minutes, even on underpowered equipment, and you can get a feel for yourself in a morning of how valuable its debuggers and viewers are likely to be in your work. My role is to recommend that doing so is likely to be worth your effort. If you spend much time programming in dynamic languages, you'll likely be more productive with Komodo."